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Port Address Translation (PAT) configuration

With Port Address Translation (PAT), a single public IP address is used for all internal private IP addresses, but a different port is assigned to each private IP address. This type of NAT is also known as NAT Overload and is the typical form of NAT used in today’s networks. It is even supported by most consumer-grade routers.PAT allows you to support many hosts with only few public IP addresses. It works by creating dynamic NAT mapping, in which a global (public) IP address and a unique port Read more […]

Dynamic NAT

Unlike with static NAT, where you had to manually define a static mapping between a private and public address, dynamic NAT does the mapping of a local address to a global address happens dynamically. This means that the router dynamically picks an address from the global address pool that is not currently assigned. The dynamic entry stays in the NAT translations table as long as the traffic is exchanged. The entry times out after a period of inactivity and the global IP address can be used for new Read more […]

Static NAT

With static NAT, routers or firewalls translate one private IP address to a single public IP address. Each private IP address is mapped to a single public IP address. Static NAT is not often used because it requires one public IP address for each private IP address.To configure static NAT, three steps are required:1. configure private/public IP address mapping by using the ip nat inside source static PRIVATE_IP PUBLIC_IP command 2. configure the router’s inside interface using the ip nat inside Read more […]

What is NAT?

NAT (Network Address Translation) is a process of changing the source and destination IP addresses and ports. Address translation reduces the need for IPv4 public addresses and hides private network address ranges. This process is usually done by routers or firewalls.An example will help you understand the concept:Host A request a web page from an Internet server. Because Host A uses private IP addressing, the source address of the request has to be changed by the router because private IP addresses Read more […]